If you choose to hire a draftsperson or architect, they may charge you based on the square footage of the area you are proposing, by an hourly rate for their time or as a percentage of the cost of the structure. Costs of building permits will be a percentage of the estimated cost of the structure you are proposing (e.g., $15 permit fee per $1000 or 1.5 percent), or a cost-per-square foot depending on your municipality (e.g., $1.20 per square foot). Design work and permits will both differ depending on the part of the country in which you will be building, so ask the questions as you move ahead. One of the costs that is often overlooked in planning is the increase in annual property tax you will pay once your improved property has been reassessed.
As the comic George Carlin might say, a shop is mostly just “a place to put your stuff.” The physical aspect of a shop is indeed simply a space of some kind — a garage, a barn, a teepee — that keeps the rain, rust, and robbers away and houses a collection of implements needed to saw, plane, slice, sand, and pound raw wood into useful objects. But just like the difference between a house and a home, what transforms a building full of tools into a comfortable workshop goes beyond the mere physical aspect.